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Patented Feb. 26,

UNITED STATES PATENT OFFICE.

CHARLES FISCHER, JIL, OF WYOMING, AND WARREN T. BEDDISH, 0F CINCINNATI,

OHIO, ASSIGNORS TO THE TWITCI'IELL PROCESS COMPANY, OF CINCINNATI,

A CORPORATION OF OHIO.

OHIO,

PROCESS OF OBTAINING PURE MINERAL OIL SULPHONATES.

No Drawing.

Our invention relates to a process of separating oil and sulphonated components thereof, and particularly to a process of fractionally extracting said sulphonated components in very pure condition.

Our invention also relates to certain prodacts of this process.

The oils embraced within the scope of this invention are hydrocarbon oils characterized by the presence of certain components susceptible to modification by the action of sulphuric acid and certain components not susceptible. Oils such as petroleum, shale oil, coal tar oil, gilsonitic distillates and many other fractions or distillates of hydrocarbon deposits usually exemplify this characteristic.

Since petroleum is commercially available at present in large quantities, the following disclosure is made in relation thereto:

l i hen petroleum or fractions thereof, such as lubricating stock, are treated with sulphuric acid, certain components of the oil are modified. The theory chemically accepted at present explains this modification as sulphonation, i. e. the sulphuric acid reacts with components of the mineral oil to form mineral oil sulphonic acid. These sulphonic bodies are characterized chemically by their high molecular weights compared with benzene sulphonic acid. The yield of sulphonic acid is higher when the oil is treated with fuming sulphuric acid, so this disclosure is also made in relation to this fuming sulphuric acid treatment.

It is further theory that these mineral oil sulphonic acids can be reacted with metallic substance or compounds such as sodium hydroxide or sodium carbonate, for instance, to produce salts of mineral oil sulphonic acid. Research to date seems to indicate that these assumptions are correct, but in the ensuing description of the invention and the claims, itis to be understood that the procedure and products thereof as described is the real substance of the invention and that the chemical explanation is merely offered for the benefit of those skilled in the art.

This above described treatment is practiced on a large commercial scale in therefining of medicinal white oil. In this refining operation the sulphonated components are the by-products and are commercially available as such at present. These sulphonated components are usually available in the form Application filed October 11, 1927. Serial No. 225,594.

of alkaline salts since the sulphonated components in' the acid state have a highly corrosive action on iron or steel pipes or containers. The advantage of treating, shipping or handling these sulphonated components in a neutral state is a continuing one.

The process of refining the white oil and extracting the sulphonates is described and claimed in U. S. Patent No. 1,087,888 to Grigori Petroff, issued February 17, 1914-; U. S. Patent No. 1,233,700 to Grigori Petroff, issued July 17, 1917 U. S. Patent No. 1,196,- 274. to Grigori Petrofl, issued August 26, 1916; and a specific process 'in U. S. Patent No. 1,286,179 to Robert E. Humphries, issued November 26, 1918.

The acid product so obtained, or reconstituted as such, is characterized when used in conjunction with sulphuric acid by its accelerating effect on the splitting of fats, for instance, in the soap industry, and also by the tendencies of some of the acids to emulsify oil and water.

These characteristics are more fully set forth in the U. S. Patents to Grigori Petrofi' No. 1,079,437, issued November 25, 1913, and No. 1,230,599, issued June 19, 1917.

The sulphonic bodies commercially available as a result of the practice of the above specified process are known as commercially pure. They are not chemically pure because of the casual presence of reaction by products or excesses, and also because these processes do not completely separate all of the oil from the sulphonated components. In fact, the oil and sulphonated components are so intimately mixed, so closely associated and/or possessed of such physical affinity for each other that complete or even approximately complete removal of all the oil has not heretotore been practical. Though it has been known that by repeating the conventional ere tractiug steps the amount of oil present can be reduced little by little, and though it has been known that purity accentuates some of the known characteristics of the products, still the commercial benefits have failed to over-balance the costof purifying to whatever extent possible according to known processes. It has not, however, been known that when these sulphonates are once suliiciently available is a result of the practice elf the Petrotl Humphries and other known commercial processes.

Another object of our invention is to provide simple, economical, commercial process of purifying mineral oil-sulphonates.

Another object of the invention is to provide a treatment for sulphonate extracting solvents said treatment adapted to increase the yield of sulphonates.

In co ni'l'iercial i .ct-ice a mineral oil fraction such as a lubricating stock is treated with sulphuric acid. Two layers are to lCCl. The upper layer is known as the A layer or oil layer and the lower layer as the B layer or sludgelayer. The A layercontaining sulphonic acids known as mahogany acids is removed and treated with dilute aqueous alcohol and sodium carbonate. Again two layers are formed. The upper layer is known as the oillayer and the lo ver layer known as the alkaline alcoholic sublye. lhe lower layer contains sodium sulpltionates known in the art as mahogany soap. The layers are parted and the aqueous alcohol is distilled from the lower layer leaving the mahogany soap with approximately 2042575 oil closely associated there Jith and also some sodium carbonate (since an excess is generally used) and some HlOlS ZLllG.

By repeatedly treating this mahogany soap with dilute aqueous alcohol. a little more of the oil can be floated elf each treatment, but the law of diminishing returns obtains.

Our invention comprises the circumventing of this law of cu; nishi-ng; returns and is based on the discovery that the tendency of the oil to go upu ar lly into layer forming sulplumate extracting solvent with the sulphonates less to marked degree than the tendency of the oil to go downvmrdlyinto said solvent with the sulphonates.

Otherwise stated It is a conventional practice to se giarate fractionally the oil from the steel-I by repeatedly producin an. upper oil strata whe r ms our invention coiuemplatcs tractionally sii-parating sulphonates from the stock by repeatedly producing an upper sulahonate strata.

We therefore separate the oil by stratification, said stratification characterized by the segregation of the oil in the lower strata. This stratification is accelerated and in some cases only produced by lowering the temperature of the liquid mass. treatment can be applied either directly to the sulphonated oil stock or to the mahogany soap stock.

The class of solvents suitable for such use comprises those solvents in which sulphonates are soluble and oil insoluble. The solvents of the alcohol series (including acetones) are at present commercially available in quantities and at prices suitable for such employment. But in order to form the upper extracting layer it is necessary that the strata producing liquid be of relatively low specific gravity, and must not therefore contain over a certain percentage of water. It too much water were present some of the oil would form an upper layer and some remain in the sulphonates. Since the price at these solvents increases with their freedom from water, it is con'unercially desirable to use a solvent as dilute as consistent with good results. It the strata producing liquid contained only solvent and water, its c'llicacy would vary directly with the proportion of solvent. But this invention includes the treatment of a strata producing; liquid to minimize the yield diu'iinishing eliccts ot the .vater therein. lhis treatment comprises treating); or preferably saturating; the strata producin liquid containing a solvent for the sulphonates and. Water with a salt adapted to keep the sulphonic bodies salted out of the vmter content of said liquid. Sodium car-- bonate, sodium chloride, potassium nitrate, and many other wat r soluble salts are adapted to perform this function. Consequently. this invention renders good yields possible with a relatively inexpensive strata producing liquid.

@ur invention therefore includes a simple process of securing; good yields of very pure oil-tree mineral oil sodium sulph matcs from a raw material such as sulphonated n'iineral oil or mahogany soap.

The stepsot this process are:

(1) Extracting); the sulphonatcs from the stock with an upper layer forming solvent.

Isolating said upper layer.

Removing said solvent from the extracted sulphonates.

In applying this invention to the mahogany soaps obtained as described in the precedinp; paragraphs, the soaps are .Iirsi dehydrated. for instance. by heating. lo remove as much u'ioisturc as possible. The twill)?! are next thoroughly mixed with prel'm'ablv ha-cc. times their volume of a :-:ol\'cul such as an alconol. Agitation for lillceu or twenty minutes. and a tciuperaliure from 150 to 175; l are usually desirable in order to zu-coiupll h a more thorough mixture. This alcohol is aqueous but preferably oi over alcoholic strength. is requisite that the solvent and its strength be so chosen in relal ion to the specilic graviy of the stool; treated, that upon settling, the solvent forms an upper layer above an oil containing; lower layer.

l l hcn a mahogany soap produced in the process of refining while oil trom American IOU Jill) 1uid-continent lubricating stock is so treated with 85% aqueous alcohol, methyl, ethyl, or denatured, the two layers form. The upper layer contains alcohol and sodium sulphonate, the lower layer contains oil, water, the excess of sodium carbonate from the initial refining, and some sulphonates.

In order to reduce the solvent action of the water and obtain a greater yield of sulphonates in the upper layer, the aqueous alcohol before introduction is supersaturated to about 15% with a salt such as sodium carbonate. This tends to keep the sulphonates salted out of the lower layer, particularly the sulphonates of highest molecular weight, and increases the yield in the upper layer to proportions justifying commercial operations. Moreover, this sodium carbonate treatment increases the specific gravity of the water in the. aqueous alcohol and facilitates stratification into the two layers. The upper layer contains alcohol, sulehonates, relatirely little water and no sodium carbonate.

The upper layer is then drawn off and the solvent distilled from the sulphonates. The residue comprises mineral oil-sodium sulphonates substantially 100% pure, free from mineral oil sodium carbonate, sodium sulphate and all other casual products or byproducts incidental to the refining operation.

V fhile this alcoholic extraction leaves all of the oil behind, it does not extract all of the sulphonates and some of them remain in the lower layer.

()ne example of a preferred purification of mahogany soap is as follows 14.00 pounds of sodium mahogany soap as obtained from the oil refineries containing approximately 71% sulphonic bodies, is heated in an open vessel at a temperature of about 105 C. for approximately three hours or until the soap is completely dehydrated. This soap is then washed with appronimatd ly two volumes of 85% aqueous alcohol supersaturated to about 15% with soda-ash. During this treatment the temperature is raised to about 75 C. and tion is continued for about one hour in order to get a very thorough mixture. The solution is then allowed to stand for six or eight hours, preferably over night, or until clear s )aration takes place. The upper layer cont 1mg the solvent and the sulphouute of high molecular weight is then decanted and the solventevaporated from the sulphouate. The residue is 1.135 pounds of pure mineral oil sodium sulphonate of high molecular weight. A second wash of the lower layer with aqueous alcohol removes additional sulphonic bodies but these are not quite as pure or of quite as high molecular weight as the first extracted bodies.

This process not only yields very pure sulphonates, but sulphonates of a very high range of molecular weights which are especially suitable and effective for fat splitting, for instance, in the soap industry. The first extraction yields sulphonates of slightly higher molecular weights than the following extractions.

In the past it has always been considered necessary to have sulphuric acid present in the splitting of fats, or at least to employ the sulphonic reagents in their acid form, but the sodium sulphonate produced by the above described process is capable of splitting high grade fats without either reconsiitution or sulphuric acid, i. e. by a neutral splitting treatment. It is also possible to split lower fats with this pure sodium sulphonate in conjunction with an amount of sulphuric acid, smaller than is conventional to use with the present acid reagent, and by reconstitut ing the sulphonates completely as acids fat splitting reagent is obtained extremely effective when used either with or without sulphuric acid.

These sulphonates are an excellent detergent. They are also Very effective for making water soluble oils or forming oil and water emulsions as is described and claimed in my co-pending application, Serial No. 225,017, filed Oct. 8, 1927.

Having described our process and certain preferred products, we desire to be limited only by the following claims:

1. In the process of producing a reagent of the class described, the step of mixing mahogany soap with an aqueous alcoholic solvent of over 7t alcoholic strength, said solvent supersaturated with sodium carbonate.

2. In the process of separating oil and sulphonated components thereof, the step of mixing said bodies to be separated with an equeous alcoholic solvent of over 75% alcoholic strength, said solvent saturated with a water soluble salt.

3. In the art of separating oil and sulphonatcd components thereof with a strata producing liquid comprising a solvent for the sulphonatcs and water, the step of reducing the solvent action of the water by saturating said liquid with a salt.

In witness whereof, we hereunto subscribe our names.

CHARLES FISCHER, Jn. WARREN T. REDDISH. 

